This invention relates to a process for the production of silicoformic cyanide and dicyanide by chemically reacting silicoformic acid (H.SiO.OH) with hydrogen cyanide in an aqueous solution and in the ratio of about 1:1 or 1:2 mols.
The silicoformic acid may be produced by the chemical reaction of a dry alkaline earth metal metasilicate or a dry alkali metal metasilicate with a mineral acid or a hydrogen containing acid salt. The silicoformic acid produced is washed with water, filtered and air dried to a granular white powder. Silicoformic acid, also known as monosilanic acid, may also be produced by other methods, such as those disclosed in U.S. Pat. Nos. 3,674,430; 3,929,972; 3,954,941; and 3,962,067.
The silicoformic acid used in the following Examples was produced by reacting dry granular alkali metal metasilicate with an hydrogen containing acid salt or a concentrated mineral acid. The white granules of silicoformic acid were washed with water, filtered, and then air dried at 25.degree. C to 75.degree. C.
The silicoformic acid granules were analyzed by Infrared analysis, using the Infrared KBr disc method. The Infrared analysis showed the presence of Si--H bonds. The Infrared analysis was very similar to that obtained with Mallinckrodt's hydrated silica except for the area which shows the presence of Si--H bonds. The Mallinckrodt's hydrated silica (SiO.sub.2.xH.sub.2 O) has a molecular weight of 60.09 . xH.sub.2 O. The silicoformic acid produced contains an active hydrogen which will reduce silver nitrate in an aqueous solution. This is evidence that Si--H bonds are present.
When the silicoformic acid produced is heated much above 105.degree. C, silicon dioxide with a molecular weight of about 60 is produced. On further heating, it has a melting point of 1650.degree. C.
In cryoscopic and ebullioscopic determination, the silicoformic acid produced was not soluble in any common organic solvent but was readily soluble in dulute alkali metal hydroxide aqueous and alcoholic solutions.
The molecular weight was determined from the boiling point elevation of the said silicoformic acid in a 6N sodim hydroxide aqueous solution and indicated a molecular weight of 78 .+-. 25 gm/mol. This type of reactive solution normally changes the molecular species. The silicoformic acid readily reacts with the sodium hydroxide. However, this would seem to indicate the absence of a polymeric form of silicate. This analysis may indicate a possible formula of HSi(OH).sub.3 (orthosilicoformic acid) and the presence of some H.sub.2 SiO.sub.3 (metasilicic acid). The orthosilicoformic acid, when dried, will lose water to form silicoformic acid.
The cyanide silicate silicoformic acid cyanide (H.sub.3 SiO.sub.2 CN) and dicyanide silicate silicoformic acid dicyanide H.sub.2 SiO.sub.2 (CN).sub.2, compounds are useful as an intermediate in the production of many organic silicates compounds, such as amine silicates, isocyanate silicates, organic silicate acids, organic ester silicates and other organic silicate compounds. The cyanide silicate and dicyanide silicate compounds are useful as fillers in varnishes and paints.
As an example of the utilization of cyanide silicate and dicyanide silicate compounds the following example is given; about 1 part by weight of the mixture of cyanide silicate and dicyanide silicate as produced by this process are mixed with 1 part by weight of diethylenetriamine and 2 parts by weight of epichlorohydrin. The epichlorohydrin is slowly added while agitating and keeping the temperature between 25.degree. to 70.degree. C at ambient pressure and agitating for 20 to 45 minutes thereby producing an epoxy resinous product, a thick liquid. The resin is poured into molds of useful objects such as gears, knobs, etc., then heated to 80.degree. to 100.degree. C thereby producing hard, tough, useful objects.
As another example of utilization of dicyanide silicate the following example is given: about 1 part by weight dicyanide silicate, 0.1 part by weight of sodium carbonate, and 2 parts by weight of methacrylic acid are mixed in 4 parts by weight of water then 0.01 parts by weight of potassium persulfate and 0.001 parts by weight of ferric sulfate are added. The mixture is then heated to about 50.degree. to 80.degree. C for 20 to 60 minutes thereby producing a resinous solid product. The resinous solid product is ground into powder then molded by heat and pressure into useful objects such as knobs, art objects, toys, etc.